Consider excelnv.exe for addition

[moshekaplan]

Source: https://twitter.com/Hexacorn/status/1396536863498907654

C:\Program Files*\Microsoft Office\root\Office*\excelcnv.exe accepts URL so you can use it as a downloader

excelcnv.exe -oice

caveat? your download will be saved as an XLSX and binary data will be stored encoded with UTF8 inside xl\sharedStrings.xml

Also from https://gist.github.com/AhnSeongHyun/3372088:

Word:
"C:\Program Files\Microsoft Office\Office12\wordconv.exe" -oice -nme

Excel:
"C:\Program Files\Microsoft Office\Office12\excelcnv.exe" -oice

PowerPoint:
"C:\Program Files\Microsoft Office\Office12\ppcnvcom.exe" -oice

예) PPCNVCOM.EXE -oice C:\b.ppt C:\b.pptx

Note that it appears to do preprocessing, so the payload may need to be base64 encoded to ensure it's not modified